# US 8,571,493 B2 · Methods and apparatus of providing transmit and/or receive diversity with multiple antennas in wireless communication systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,571,493 B2 - Document ID: US8571493B2 - Status: Granted - Kind: B2 - Application number: 12/606,079 - Filed: 2009-10-26 - Published: 2010-02-18 - Granted: 2013-10-29 - Earliest claimed: 2003-10-16 - Assignees: QUALCOMM Incorporated - Applicants: Rajiv Laroia; Junyi Li; Sundeep Rangan; Murari Srinivasan; Frank A. Lane; Prashanth Hande - Inventors: Rajiv Laroia; Junyi Li; Sundeep Rangan; Murari Srinivasan; Frank A. Lane; Prashanth Hande - Web page: https://patentgrep.com/patent/US8571493B2 ## CPC - H04B 7/0604: {with predefined switching scheme} - H01Q 3/24: varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching - H01Q 3/2605: {Array of radiating elements provided with a feedback control over the element weights, e.g. adaptive arrays} - H04B 7/0691: {using subgroups of transmit antennas} - H04L 5/0026: {Division using four or more dimensions, e.g. beam steering or quasi-co-location [QCL]} - H04W 52/42: in systems with time, space, frequency or polarisation diversity - H04B 7/061: {using feedback from receiving side} - H04B 7/0805: {with single receiver and antenna switching (H04B7/0822 takes precedence)} - H04L 1/0026: {Transmission of channel quality indication} - H04L 5/0007: {the frequencies being orthogonal, e.g. OFDM(A) or DMT} - H04L 5/0023: {Time-frequency-space} - H04L 5/006: {Quality of the received signal, e.g. BER, SNR, water filling} - H04B: TRANSMISSION - H01Q: ANTENNAS, i.e. RADIO AERIALS (radiators or antennas for microwave heating H05B6/72) - H04L: TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION (arrangements common to telegraphic and telephonic communication H04M) - H04W: WIRELESS COMMUNICATION NETWORKS (broadcast communication H04H; communication systems using wireless links for non-selective communication, e.g. wireless extensions H04M1/72) ## Abstract Transmit and/or receive diversity is achieved using multiple antennas. In some embodiments, a single transmitter chain within a wireless terminal is coupled over time to a plurality of transmit antennas. At any given time, a controllable switching module couples the single transmitter chain to one the plurality of transmit antennas. Over time, the switching module couples the output signals from the single transmitter chain to different transmit antennas. Switching decisions are based upon predetermined information, dwell information, and/or channel condition feedback information. Switching is performed on some dwell and/or channel estimation boundaries. In some OFDM embodiments, each of multiple transmitter chains is coupled respectively to a different transmit antenna. Information to be transmitted is mapped to a plurality of tones. Different subsets of tones are formed for and transmitted through different transmit chain/antenna sets simultaneously. The balance of tones allocated to the subsets for each antenna are changed as a function of predetermined information, dwell information, and/or channel condition feedback information. ## Claims ### Claim 1 A wireless terminal, comprising: a switching module that operatively couples a transmitter signal processing chain to a set of antenna elements, wherein the switching module performs switching on signal boundaries corresponding to base station channel estimation reset points; and a switching control module that controls the switching module to switch between respective antenna elements of the set of antenna elements on one or more signal boundaries corresponding to a subset of the base station channel estimation reset points, wherein the switching between respective antenna elements is preceded or followed by at least one dwell, the at least one dwell is a period of time during which the wireless terminal employs a single set of tones to transmit signals to a base station. ### Claim 2 (depends on 1) The wireless terminal of claim 1, further comprising: a receiver switching control module that operatively couples a receiver signal processing chain to a second set of antenna elements, wherein the receiver switching module is configured to perform switching after receiving groups of symbols, the groups of symbols comprise one or more orthogonal frequency division multiplexing symbols; and a receiver switching control module configured to control the receiver switching module to switch between respective antenna elements of the second set of antenna elements, wherein the switching between respective antenna elements of the second set is preceded or followed by at least one second period of time during which the wireless terminal employs a single antenna element of the second set to receive one or more groups of symbols. ### Claim 3 (depends on 2) The wireless terminal of claim 2, the receiver switching control module is configured to control the receiver switching module to switch between respective antenna elements of the second set based at least in part on a predetermined switching sequence. ### Claim 4 (depends on 2) The wireless terminal of claim 2, the receiver switching control module is configured to control the receiver switching module to switch between respective antenna elements of the second set based at least in part on a quality of a received downlink signal. ### Claim 5 (depends on 1) The wireless terminal of claim 1, the switching control module controls the switching module to switch between respective antenna elements of the set based at least in part on a fixed predetermined switching sequence. ### Claim 6 (depends on 1) The wireless terminal of claim 1, further comprising an uplink channel feedback module configured to receive quality indicator signal information that corresponds to a quality of one or more signals sent to the base station, the uplink channel feedback module is configured to provide at least one feedback quality level based on the quality indicator signal information to the switching control module, the at least one feedback quality level is associated with at least one antenna element of the set of antenna elements, wherein the switching control module controls the switching module to switch between respective antenna elements of the set of antenna elements based at least in part on the at least one feedback quality level. ### Claim 7 (depends on 6) The wireless terminal of claim 6, the switching control module is configured to control the switching module to switch between respective antenna elements of the set based at least in part on the at least one feedback quality level. ### Claim 8 (depends on 6) The wireless terminal of claim 6, the quality indicator signal information includes at least one set of quality information associated with the at least one antenna element. ### Claim 9 (depends on 6) The wireless terminal of claim 6, the uplink channel feedback module correlates the quality indicator signal information with the set of antenna elements to produce the at least one feedback quality level. ### Claim 10 (depends on 6) The wireless terminal of claim 6, the quality indicator signal information comprises transmission power control signal information associated with a signal received at the base station from the wireless terminal, the transmission power control signal information is based on at least one of a power level, a relative power level, a signal to noise ratio, or a commanded power level change. ### Claim 11 (depends on 6) The wireless terminal of claim 6, the quality indicator signal information comprises transmission acknowledgement signal information that indicates a success rate associated with a signal received at the base station from the wireless terminal. ### Claim 12 (depends on 6) The wireless terminal of claim 6, the switching control module controls the switching module to switch to a first antenna element of the set of antenna elements more frequently than a second antenna element of the set of antenna elements based at least in part on the at least one feedback quality level. ### Claim 13 (depends on 6) The wireless terminal of claim 6, the switching control module controls the switching module to switch to a first antenna element of the set of antenna elements instead of a second antenna element of the set of antenna elements based at least in part on the at least one feedback quality level. ### Claim 14 A method of providing increased diversity in a wireless communication system, comprising: coupling a first antenna element of a set of antenna elements to a transmitter chain; transmitting an uplink signal to a base station via the first antenna element using a first set of tones during a first set of time intervals; switching from the first antenna element to a second antenna element of the set of antenna elements; and transmitting the uplink signal to the base station through the second antenna element using a second set of tones during a second set of time intervals. ### Claim 15 (depends on 14) The method of claim 14, further comprising receiving at least one feedback signal from the base station that indicates a quality of the uplink signal. ### Claim 16 (depends on 15) The method of claim 15, further comprising correlating the at least one feedback signal with an associated antenna element of the set of antenna elements. ### Claim 17 (depends on 16) The method of claim 16, further comprising selecting the second antenna element from the set of antenna elements based at least in part on the at least one feedback signal. ### Claim 18 (depends on 16) The method of claim 16, switching from the first antenna element comprises: comparing the at least one feedback signal to at least one stored threshold; and selecting the second antenna element from the set of antenna elements based at least in part on comparing the at least one feedback signal to the at least one stored threshold. ### Claim 19 (depends on 14) The method of claim 14, switching from the first antenna element comprises: determining that a channel estimation boundary has been reached; and switching from the first antenna element to the second antenna element at the channel estimation boundary. ### Claim 20 A system for providing increased diversity in a wireless communication system, comprising: means for coupling a first antenna element of a set of antenna elements to a transmitter chain; means for transmitting an uplink signal to a base station via the first antenna element using a first set of tones during a first set of time intervals; means for controlling a switch from the first antenna element to a second antenna element of the set of antenna elements; and means for receiving at least one feedback signal from the base station that indicates a quality of the uplink signal. ### Claim 21 A non-transitory computer readable medium for providing increased diversity in a wireless communication system, the computer readable medium having instructions stored thereon that are executable by a processor, the instructions comprising: instructions for coupling a first antenna element of a set of antenna elements to a transmitter chain; instructions for transmitting an uplink signal to a base station via the first antenna element using a first set of tones during a first set of time intervals; instructions for controlling a switch from the first antenna element to a second antenna element of the set of antenna elements; and instructions for receiving at least One feedback signal from the base station that indicates a quality of the uplink signal.